Reduced physical function significantly increases mortality risk of middle-aged people living with HIV

HIV infection is associated with reduced physical performance, investigators report in the online edition of AIDS. They also found that people living with HIV who had reduced physical function had a significant increase in their mortality risk.

The study population comprised middle-aged HIV-positive and HIV-negative people in Baltimore, United States, who either currently inject drugs or had previously injected drugs.

“Our findings highlight the substantial impact of HIV disease on physical performance, support the growing recognition and importance of chronic HIV disease on age-related outcomes, and can inform strategies for the clinical management of aging HIV-infected persons,” comment the authors.

Glossary

person years

In a study “100 person years of follow-up” could mean that information was collected on 100 people for one year, or on 50 people for two years each, or on ten people over ten years. In practice, each person’s duration of follow-up is likely to be different.

Thanks to improvements in treatment and care, an increasing proportion of people with HIV are living into old age. This means that the diseases of ageing are now an important cause of death in these patients.

Reduced physical function is associated with increased mortality risk for older people in the general population. Function in the lower body – ability to balance, walking speed, and standing up from a sitting position – can be assessed using the short physical performance battery (SPPB). In the general population, a SPPB score below ten is associated with an increased risk of disability, admission to nursing care and mortality.

Using the SPPB, investigators wanted to see if having HIV was associated with reduced physical function. They also wished to see if physical performance had an association with mortality risk in people living with HIV.

They therefore prospectively evaluated physical performance and mortality risk in a cohort of 1627 HIV-positive and at-risk current and former injecting drug users. Physical performance was measured every six months. Follow-up lasted between 2005 and 2010, and the participants contributed a total of 12,270 study visits.

Participants had a median age of 51 years, most were African American and a third were women.

The participants living with HIV contributed 3715 study visits (30%). Their median CD4 count and viral load were 340 cells/mm3 and 70 copies/ml, respectively.

SPPB scores of ten or less accounted for a third of study visits.

After taking into account potential confounders, HIV infection was independently associated with a 30% increase in the risk of a SPPB score of ten or below (OR = 1.30; 95% CI, 1.12-1.52).

During follow-up, 165 patients (10%) died. This meant that the mortality rate was 2.75 per 100 person-years.

A SPPB score of ten or below was associated with a 2.3-fold increase in mortality risk compared to a higher SPPB score (HR = 2.34; 95% CI, 1.67-3.27). For HIV-negative patients, a lower SPPB score was associated with a 2.21-fold (95% CI, 1.37-3.55) increase in mortality risk, compared to a 2.55-fold (95% CI, 1.33-4.76) increase for HIV-positive people with poorly controlled HIV, and a 2.02-fold (95% CI, 0.95-4.3) increase for all other HIV-positive individuals.

HIV infection alone was shown to be associated with an almost three-fold increase in mortality risk (HR = 2.78; 95% CI, 1.70-4.54).

The authors found that reduced physical performance and HIV infection had a joint effect on mortality risk.

People living with HIV who had low SPPB scores had a six-fold increase (HR = 6.03; 95% CI, 3.80-10.0) in the risk of death during follow-up compared to HIV-negative individuals with higher SPPB scores.

“Our findings highlight the need to integrate geriatric principles such as functional assessment into the care of older HIV-infected adults,” conclude the authors. “The SPPB may be an effective tool for use in both clinical and research settings to support the healthy aging of persons with HIV infection.”

References

Greene M et al. The relationship of physical performance with HIV disease and mortality: a cohort study. AIDS 28, online edition. DOI: 10.1097/QAD.0000000000000507 (2014).

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